Process and apparatus for cracking petroleum oil



. R. 'r. POLLOCK PROCESS AND APPARATUS FOR CRACKING PETROLEUM OIL I May 10 Original Filed Dec. 6, 1920 v All 67 in Y N W w f 2% umvt ammvfi Patented May 10, 1927.

UNITED STATES PATENTOFFICEQ 301mm 1*. POLLOCK, OF- BOSTON, MASSACHUSETTS; ASSIGNOR To UnivERsAL on."

PRODUCTS COMPANY, OF CHICAGO, ILLINOIS,

A CORPORATION OF SOUTH DAKOTA.

rnoonss AND APPARATUS non CRACKING rnzrnonnuu 011..

Application filed December 6, 1920, Serial No. 428,790. Renewed October 6, 1926.

This invention relates to improvements in process and apparatus for cracking petroleum oil and has as its salient feature subjecting the reflux condensate and raw oil or reflux condensate alone to distillation at atmospheric pressure or under a lower pressure than that at which the main apparatus is operated. The object of this is to prevent oil already sufliciently light from being returned to the system for cracking.

In the drawing, the single figure is a view partly in section and partly in side elevation, of my improved apparatus for carrylng out the process.

Referring in detail to the drawlng, 1 designates the furnace in which is mounted the heating coil 2., This heatlng coil 2 which maybe of 2" to 6 pipe has its upper or discharge end connected by transfer line 3 provided with a suitablethrottle valve 4 to vapor. chamber 5. This vapor chamber 5 has liquid drawofi 6 provided with throttle valve 7, vapor outlet pipe 8 having throttle valve 9 and a downwardly inclined exten-' sion 9 leading to the lower side of dephleg mator 10. This dephlegmator 10 is provided with suitable baflies 12 and at its upper end has anipple '13 connected to vapor outlet pipe 14, the latter having throttle valve 15. The pipe 14 in turnis connected to conden ser coil 16 seated in condenser box 17. The condenser coil 16 is connected at its lower end by pipe 18 having throttle valve 19 to the upper part of receiver 20. This receiver 20 is provided with pressure gauge 21, llquld I level gauge 22, gas outlet pipe 23, having throttle valve 24, liquid drawofi' pipe 23 having throttle valve 26. Raw oil is supphedby pump 27 and feed line 28 provided with throttle valve 29, the 'pipe 28 being connected to nipple 30 at the upperend of the dephlegmator. Thelower end of the de hlegmator is connected by line 31 to the stil 32. This still 32 is mounted in suitable setting 33 and is adapted to be heated by the ,flue gases from the flue 34 leading from the furnace. In other words, the flue gases are utilized for heating the still 32. The unvaporlzed por'-. tion of the oil in the still 32 including both raw oil and reflux condensate is delivered by feed line 36 and pum 36 to the heating tubes 2 The still 32 is provided with the vapor outlet 38 having throttle valve 39 leading to condenser coil 40 seated in condenser box 41. The lower end of the coil 1s coneither mixed with the preheated raw oil nected to the upper part of receiver 42, which receiver is equippedwith an outlet pipe 43 having throttle valve 44. The ar-f rangement is such that the reflux condensate and preheated fresh oil are delivered to the still 32 where they may be heated to a. temperature of say, 450 degrees E, if that is the end point of gasoline desired, so as to drive off t ose oil constituents which are already sufliciently light. The unvaporizedportion is delivered to the feed line 36, and pump 36' to the heating coil 2. If desired, instead of feedlng the raw oil into the dephlegmator, the valve 29 may be closed and raw oildrawn in by the pump '36. through line 45--. having valve 46 and connected to the feed supply. In this case only the reflux condensate will be subjected to distillation in the still 32.

ceiver may bemaintained under a pressure of say, 151pounds to the square inch, and the oil while in liquid phase at a temperature of say, 70 0 degrees F., assuming petroleum gas oil is used. The .refiux condensate from the dephlegmator or alone may be distilled at atmospheric pressure and heated to say, 450 degrees F., or it may be distilled under a pressure-of say, 50 pounds and a temperature of 500 degrees 'F., so as to produce a slight cracking. However, normally believeit ,would be better to distill this reflux. condensate at atmospheric ressure. The process may be further modifie by distilling the reflux condensate either mixed with the preheated raw oil or of itself under a vacuum, which can be accomplished by putting a vacuum pump (not shown) on the outlet line 43.

I claim as myinvention:

,1. A process of cracking petroleum oil, consisting in subjecting the oil to a cracking temperature under a superatmospheric'pressure-to cause substantial vaporization, subjecting the generated vapors to a reflux condensing aet-ion by passing them, prior to any substantial cooling action, to a reflux con- 105 denser, delivering the reflux condensate to a "still where it is subjected to distillation at atmospheric pressure to, vaporize thosecon- "stituents that are of the desiredpredeterl\ a reflux condenser also maintained under a superatmospheric pressure, delivering reflux condensate to a still where it is subjected to distillation at substantially atmospheric pressure to release those constituents that are of the desired predetermined end point, then returning the liquid portions of said reflux condensate to the cracking zone, and heatin said atmospheric still by the flue gases rom the furnace of the cracking zone.

3.,A process of crackin petroleum oil consisting in heating the 011 to a cracking temperature to cause substantial vaporization, subjecting the generated vapors to reflu'x condensing action by passing them, prior to being subjected to any substantial cooling action, to a reflux condenser,

delivering the reflux condensate separated from thevapors undergoing reflux condensation to a still where it is subjected .to substantially atmospheric distillation to release those constituents that are of the desired predetermined end point, then returning the liquid portions of said reflux condensate to the cracking zone, maintainin a pressure on said cracking zone and re ux condenser in 7 excess of 50 pounds to the sqifiire inch, and in heating said atmospheric sti I 4. A process of cracking petroleum oil consisting in heating the oil to a cracking temperature in a main cracking zone to cause substantial vaporization, subjecting the generated vapors to reflux condensing action by passing them directly to a reflux condenser, delivering the reflux condensate to a still where it is subjected to atmosphericdistillation to drive off those constituents that are of the desired predetermined end point, then returning the liquid portions of said reflux condensate to the main cracking zone, maintaining a pressure on said cracking zone and reflux condenser in excess .of 50 pounds to the square inch, and in heating said atmospheric still. I

5. A process for converting high into low boiling point hydrocarbons, consisting in cracking'the oil in a heating zone under pressure, subjecting the oil vapors to a dephlegmating action in a reflux condenser, condensing the low boiling point oil vapors subsequent to dephlegmation, recovering the low boiling point cuts froin the reflux condensate by retreatment thereof in a zone of lower pressure than that maintained in the \reflux condenser and combining the unvaporized reflux condensate from the zone of retreatment with raw oil prior to cracking.

6. A continuous process for converting high into low boiling point hydrocarbons, consisting in cracking the oil in a heating zone under pressure of the generated vapors, subjecting the oil vapors to a dephlegmating action in a deflux condenser, condensing the low boiling point oil vapors subsequent to dephlegmation, recovering the low boiling point oil fractions from the reflux condensate in a zone of lower pressure than the reflux condenser, combining the unvaporized reflux condensate and raw oil in regulated proportions prior to cracking.

7. A continuous process for converting high into low boiling point hydrocarbons, consisting in cracking the oil in a heating zone under pressure of the generated vapors. subjecting the oil vapors to a dephlegmating action in a reflux condenser, condensin the low boiling point oils subsequent to dephlegmation, recovering the low boiling polnt' oil fractions from the reflux condensate iniia heated zone of lower pressure than that maintained in the reflux condenser, combining the unvaporized reflux condensate and preheated raw oil inregulated proportions prior to-cracking.

8. In an apparatus for converting high into low boiling point hydrocarbons, the combination with a means for cracking the oil, of a reflux condenser for dephlegmating the generated oil vapors, means for delivering the generated oil vapors to said reflux condenser, condensing means for recovering the low boiling point vapors, a still connected to the reflux condenser adapted to extract the low boiling point oils from the reflux condensate, means for combining the reflux condensate with the raw oil prior to cracking, and means for maintaining a pressure upon the apparatus during operationl 9. A continuous process for converting high into low boiling point hydrocarbons, consisting in crackin the oil in a heating zone under pressure 0 the generated vapors, subjecting the vapors to a dephlegmating action in a reflux condenser and passing the reflux condensate to a separate zone of treatment and there retreating it under a lower pressure than that maintained in the reflux condenser, separately condensing the dis tilled oil constituents from the separate zones of treatment and returning the unvaporized reflux condensate and mixing it in controlled quantities with the oil charged to, the initial heating zone.

' 10. A continuous process for'converting high into low boiling point hydrocarbons, consistin in cracking the oil in a heating zone under a pressure of the generated vapors, subjecting the evolved vapors to a dephlegmating action in a reflux condenser,- retreating the 1 reflux condensate under a zone, 'while under pressure of the it in regulated quantities with the charging oil supplied to the process.

11. A process for'converting point hydrocarbons into low boiling point hydrocarbons, consisting in subjecting the oil to a cracking temperature in a heating generated vapors evolved high boiling vapors, in subjecting the from the oil to dephlegmation, in retreating the reflux condensate resulting from such dephlegmation under a lower pressure, to

- separate substantial quantities of the lighter oil constituents therefrom, in uniting the heavier constituents of the reflux condensate with the charging oil'for the process in predetermined proportions, and in supplying the resulting mixture to the heating zone.

' 12. A process for converting high boiling point hydrocarbons into low boiling point hydrocarbons, consisting in subjecting the oil to be converted to cracking conditions in a heating zone, in dephle'gmating vapors released from the oil in a dephlegmating zone, in effecting a removal of the lighter from the heavier constituents of the heated reflux condensate without again subjecting said constituents to further treatment in the heat ing zone separated from the vapors. undergoin dephlegmation, in azone apart from the ephlegmating zone-rand in which no dephlegmating action. of the vapors or substantial crackingof the oil is occurring, in recovering the lighter constituents removed .from the heavier'constituents of the refluxcondensate, and in continuously returning the heavier constituents of the reflux condensate to said heating zone for further treatment in the process.

13. A rocess for converting high boiling point by rocarbons into lower boiling point hydrocarbons, consisting in subjecting the oil to a cracking treatment in a heating zone, in permitting vaporization of the oil in a suitable vapor space, pors evolved from the tion in a reflux condensing zone, in passing the heated reflux condensate separatedfrom the vapors undergoing reflux condensation to a separate zone, in which no substantial cracking takes lace or dephlegmation of vapors occurs, w erein the reflux condensate is subjected to further treatment, to remove therefrom substantial quantities of the low boiling point fractions which have combined with .the reflux condensate during the reflux condensing action, in recovering such low boiling point fractions and in continuously returnin the heavier constituents of the reflux con ensate, from which such lower boilpoint hydrocarbons into low boilin in subjecting the'va oil' to reflux condensa-.

ing point fractions were separated, to said heating zone. to be subjected to further treatment in the process. I

14. A process for converting high boiling point hydrocarbons, oil to a cracking treatment in a heating zone, in transferring the heated Oil from said heating zone to a second "zone, where substan tial vaporization occurs, in subjectingthe vapors generated from the oil to dephlegmation in a dephlegmating zone, in removing the reflux condensate separated from the vapors undergoing dephlegmation from the dephlegmating zone to an evaporating zone. wherein no substantial cracking or dephlegmating action occurs and wherein the lighter gasoline-like constituents are evaporated from the heated reflux condensate, in recovering the lighter constituents evaporated from the heated reflux .con densate and in continuously returning the heavier constituents of the reflux condensate, the removal of such lighter constituents, to the heating zone, to be again subjected to a cracking treatment.

15. In an apparatus for crackin oil, the combination with a still, of a re consisting in subjecting the subsequent to denser for receiving the vapors therefrom,

means for conveying reflux condensate from said reflux condenser to a separate zone, means for taking off light oil constituents m vaporous form from said second'zone,

means for maintaining a lower pressure in said separate zone than is maintained in said reflux condenser, and means for returning heavier constituents of the refiux condensate from such separate zone to said still for further treatment.

16. A process for converting high boiling point hydrocarbons into relatively lower boiling point hydrocarbons, consistln in subjecting the hydrocarbon oil to crac ing conditions of temperature and pressure in a still, in subjecting the vapors evolved from the oil to dephlegmation, in collecting the reflux condensate separated from the vapors,

as a result of suchdephlegmation, in a zone wherein'such reflux condensate is maintained out of contact with the undephlgmated vapors evolved from the oil undergoing con- Tversron in the process, in efi'ectlng an evaporation of the light gasoline-like constituents from the heavier constituents of the heated reflux condensate in such zone, in recoverlng the evaporated light gasoline-like constituents, and in continuously returning the heavier unvaporized constituents of the reflux condensate, subsequent to the removal of such light gasoline-like constituents therefrom, to the cracking still, to be again subjected to cracking conditions ,of temperature and pressure.

17. A process for converting high boiling point hydrocarbons into relatively lower boiling point hydrocarbons,

consisting in subjecting the hydrocarbon oil to be treated to cracking conditions of temperature and pressure in a still, in subjecting'the vapors evolved from the oil to dephlegmation 1n a reflux condensing zone, in admitting the re flux condensate separated from such vapors to an evaporating zone in which the reflux condensate is maintained out'of contact with the undephlegmatedva ors passing from the still to the reflux con ensing zone, wherein the light gasoline-like, constituents are evaporated from the heavier constituents of the reflux condensate, and in assistin in the rating zone, in recovering the evaporated gasoline-like constituents, and in continuously returning the heavier unvaporized constituents of the reflux condensate, subsequent .to the removal of the light gasoline-like constituents therefrom, to the cracking still to be again subjected to cracking conditions of temperature and pressure.

' ROBERT T. PQLLOCK. 

